<template>
    <h1>我是demo组件</h1>
    {{ sum }}
</template>

<script>
import { ref } from "vue";
export default {
    name: "Demo",
    async setup() {
        const sum = ref(0);

        return await new Promise((resolve, reject) => {
            setTimeout(() => {
                resolve({ sum });
            }, 3000);
        })
    }
};
</script>
